Monday, 29 June 2015

#30DaysWild Day 28: Glowworms

We had a night time adventure on Saturday night, joining a guided walk organized by the Chiltern Society to look for glow worms on Brush Hill. Bug Mad Girl and I had looked for them this time last year without any success, but I think we gave up too early in the evening (as it was a bit scary up there on our own!) and we weren't really sure what we were looking for. This time we had safety in numbers and were with John Tyler, who knows everything there is to know about glow worms.

We got out onto the hill at about 10pm, just as it was getting dark. The view was even more amazing in the twilight, with Princes Risborough at the bottom the hill and the lights of Aylesbury, Oxford and Didcot off in the distance.

We split into two groups and started searching for the green light emitted by the female glow worms. They were quite hard to spot as they were low down in the grass and you had to be almost on top of them to see them. When we'd found the first one, we at least knew what we were looking for and soon found more, even though it involved quite a lot of crashing around in the dark.

Glow worms are actually beetles from the firefly family. It's only the female that produces the green light, from the last few segments of her abdomen. She's completely wingless, so glows to attract the smaller, winged males. She spends two years as a larvae, then pupates in a burrow in the ground emerging in June or July. She climbs out of the burrow, glows, mates then crawls back into the burrow to lay her eggs. She dies soon afterwards and is only an adult glow worm for about a week.

Female glow worm

Mating glow worms

At one point John found a female glow worm and several males. He picked them up so we could take a closer look and realised that the female actually had one wing. He believes this is the first recorded case of a hermaphrodite glow worm! He took her home to photograph and study and was going to return her to the same spot the next day.

3 winged male glow worms and one larger female (with one wing)

Hermaphrodite glow worm

We found another glow worm and everybody had the chance to hold it. We made sure she was put back in exactly the same place as we found her so she could crawl back into her burrow.

What an adventure!

We left the moth trap out overnight and checked it first thing in the morning (still in pyjamas!)

It was full of moths, but we also found a male glow worm in it. I think we would have just thought it was a little black beetle if we hadn't seen them the night before. It's exciting to think there are glow worms in our back garden!

1 comment:

Brilliant stuff! I've seen a glowing glow-worm a couple of years ago while watching nightjars. Maybe that should be your next night time challenge? Nightjars make a strange sound and they are amazing to hear. You will love it!